This section is intended to introduce the reader to various aspects of art that may be related to various aspects of the presently described embodiments. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present embodiments. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art.
In order to meet consumer and industrial demand for natural resources, companies often invest significant amounts of time and money in finding and extracting oil, natural gas, and other subterranean resources from the earth. Particularly, once a desired subterranean resource such as oil or natural gas is discovered, drilling and production systems are often employed to access and extract the resource. These systems may be located onshore or offshore depending on the location of a desired resource. Further, such systems generally include a wellhead assembly through which the resource is accessed or extracted. These wellhead assemblies may include a wide variety of components, such as various casings, valves, fluid conduits, and the like, that control drilling or extraction operations.
Subsea wellhead assemblies typically include control pods that operate hydraulic components and manage flow through the assemblies. The control pods may route hydraulic control fluid to and from blowout preventers and valves of the assemblies via hydraulic control tubing, for instance. When a particular hydraulic function is to be performed (e.g., closing a ram of a blowout preventer), a control pod valve associated with the hydraulic function opens to supply control fluid to the component responsible for carrying out the hydraulic function (e.g., a piston of the blowout preventer). To provide redundancy, American Petroleum Institute Specification 16D (API Spec 16D) requires a subsea wellhead assembly to include two subsea control pods for controlling hydraulic components and the industry has built subsea control systems in this manner (with two control pods) for over forty years. This redundant control ensures that failure of a single control pod of a control system does not result in losing the ability to control the hydraulic components of the subsea stack. But such a failure of a single control pod causes the system to no longer comply with API Spec 16D, often leading an operator to shutdown drilling or other wellhead assembly operations until the malfunctioning control pod can be recovered to the surface and repaired. In the case of deep water operations, such recovery and repair can often take days and may cost an operator millions of dollars in lost revenue. Consequently, there is a need to increase the reliability of subsea control systems to reduce downtime and costs of operation.